“Behind the Candelabra” is not the first TV movie about flamboyant piano man Liberace and his secret decade-long relationship with his “chauffeur” Scott Thorson. In 1988, a year after Liberace’s death from AIDS-related complications, dueling television films aired. Campfests, they reminded the people of that era of their lousy gaydar — that mainstream society had allowed a lifelong bachelor who rocked flowing robes and heavy rings on each finger to become the world’s highest paid entertainer. Steven Soderbergh’s new film — and possibly his last — isn’t quite as crass. Like some of the director’s recent work, it’s detached and slyly intelligent, even as it subscribes to a tried-and-true genre structure.

In this case, it finds him making his twist on a bad relationship movie. Matt Damon plays Thorson, a strapping animal trainer with a Farah Fawcett flip ‘do who meets Liberace (Michael Douglas) when he’s 18. (Damon, incidentally, is 42.) The two wind up together for a decade, some of it warm and magical, much of it unpleasant and nightmarish. Liberace grants him access to his world of tacky excess, but it won't be long until the fiftysomething sugar daddy, already obsessed with his own decaying looks, starts eyeing newer models.

Richard LaGravenese’s script deserves a lot of credit for not shying away from gay content, which is one reason this is playing on HBO, not in the nation’s multiplexes. But it follows the expected trajectory: The polite, vaguely stupid Thorson eventually succumbs to “Boogie Nights”-style coke tirades. But Soderbergh’s cold and bemused tone neutralizes the insanity. Gaudy jewelry, hirsute men and Roman columns become matter-of-fact, just part of Thorson’s day-to-day. He also brings out some of the story's weirder elements. The craziest tidbit is that Liberace convinced Thorson to undergo plastic surgery to look more like him. Soderbergh’s characters regularly delude themselves, but here they do it through plastic surgery, even if the process makes them look like freaky gargoyles. (Damon’s fake nose is creepy, but it’s got nothing on the squinty look frozen on Rob Lowe's predatory plastic surgeon's face.)

Predictably, Douglas walks off with the movie. It’s not just an impersonation, but a performance that finds notes of vulnerability (and monstrousness) buried under pounds of affectation and furs. But don’t discount Damon. The real Thorson may have been an idiot — he currently sits in jail for credit card fraud — but as portrayed by Damon, he's thick without being an idiot, as though he was aware he was making bad decisions but not smart enough to think of a way out that didn’t involve drugs and tantrums.